Bifidobacterium have long been recognized as a desirable resident of the mammalian digestive tract. Colonization of the gut by these bacteria is believed to occupy niches that might otherwise be filled by pathogenic microorganisms, particularly gram negative bacteria. Bifidobacterium are also believed to produce many products, such as vitamins, which are beneficial to the host. Promoting the growth of Bifidobacterium in human infants in particular has been recognized as being important to the development of disease resistance. See, e.g., U.S. Pat. No. 2,697,663; U.S. Pat. No. 2,872,382.
In order to enhance colonization of the human intestinal tract by Bifidobacterium, a number of products have been developed. For example, live bacteria have been marketed as a medicine or foodstuff. This approach is disadvantageous, however, because the bacteria must be maintained in a viable state. Furthermore, bacteria exogenous to the host often have difficulty in colonization because of competition with native microorganisms. Another approach has been to market sugars, such as fructose oligosaccharides, which are among the beneficial compounds produced by Bifidobacterium. This approach is also undesirable, however, since the manufacture of these compounds is relatively expensive and high dosages are required to achieve an effect comparable to enhanced colonization by Bifidobacterium. Nor does this administration of the these compounds protect the host from colonization by pathogens.
Instant tea has been prepared by a number of methods, typically involving spray drying a hot water infusion of the tea. A primary goal of these techniques is to retain the flavor of the liquid tea drink. U.S. Pat. No. 1,520,122, describes evaporating a water infusion of tea to dryness at low pressure, treating the distillate with a solvent to recover aroma and flavor compounds, and then reintroducing these compounds to the solids recovered from the water infusion. U.S. Pat. No. 3,532,506 is directed to extracts from coffee, tea or chicory where an aqueous extract and a liquid carbon dioxide extract are combined prior to freeze-drying the material. U.S. Pat. No. 3,163,539 is directed to an instant tea composition wherein a water extract is treated with oxygen under alkaline conditions to increase the proportion of cold water-soluble solids. U.S. Pat. No. 4,048,344 is directed to a continuous method of making an aqueous tea extract and freeze-drying the resulting material. U.S. Pat. No. 4,130,669 is directed to a steam extraction of tea, followed by freeze-drying the extract. A tea volatile concentrate is prepared by contacting frozen condensate with the aqueous tea extract.
A continuing need exists for improved methods of promoting the growth of Bifidobacterium in mammalian hosts, such as humans. It would be particularly desirable if a method could be developed that does not require the use of live bacteria, or the use of expensive, high-dosage products. It would also be extremely desirable if any product developed would not have any strong flavor, so that it could be readily formulated with a variety of foods.